Overrunning clutches, especially roller clutches, typically have a cage, which retains a plurality of wedging rollers and which is adapted to be installed within the annular space between coaxial inner and outer clutch races. After the clutch is installed, each roller is resiliently urged in a selected circumferential direction by a respective one of a plurality of roller energizing springs. The energizing springs thus maintain the rollers in a ready position to wedge between the inner and outer races, thereby permitting relative rotation between the races in only one direction. In some clutches, the spring is apparently not directly attached to the cage, and is held in place only by virtue of the fact that is compressed between its respective roller and some structural part of the cage. For example, see U.S. Pat. No. 4,415,072 to Shoji et al, FIG. 8. However, it is often desirable that the spring be directly attached to the cage. This is an advantage during operation of the clutch, as it helps to keep the spring aligned and in the proper operating position, and it also makes the clutch, a unitary, easily shipped and handled assembly.
Most roller clutch cage structures, whether formed of metal only, plastic only, or a composite of the two, have axially spaced side rails joined together by cross bars. These cross bars usually have a rectangular cross section with an axially extending length, radially extending width, and circumferentially extending thickness. They may be referred to as vertical cross bars, by virtue of their usual orientation on the drawn page. Vertical cross bars provide convenient anchor points at which to attach the springs. Often, the energizing spring is of the accordion type, meaning that it has a plurality of V or U shaped folds. The outer side of the last fold of the spring may be conveniently referred to as the spring tail. One fold of each spring, which may be the last fold or the next to last fold, is pressed closely over a vertical cross bar, and may be referred to as the mounting fold. This close interfit of the spring mounting fold and vertical cross bar gives the spring a stiff and solid mounting, but is, by itself, generally not sufficient to complete the attachment of the spring to the cage.
To complete the spring attachment, some kind of positive retention of the spring to the cage is desirable. It is possible to achieve that positive retention by permanently wrapping or deforming some portion of the spring mounting fold around the vertical cross bar. However, it is far more convenient from a manufacturing and assembly standpoint to provide the spring with an automatically acting latch, such as a resilient tab that flexes out of the way as the mounting fold is pressed into place, and which then flexes back over an edge of the vertical cross bar. A good example may be seen in U.S. Pat. No. 4,422,537 to Ritter et al. There, the last fold of the spring 6 is the mounting fold, and as it is pressed over the vertical cross bar 9, a resilient tab 13 lanced out of the tail of spring 6 clicks into a slot 14 through vertical cross bar 9, see FIG. 3. With such a retention scheme, however, the strength of the latch is limited by how far the tab can overlie the circumferentially extending edge of the vertical cross bar, that is, it is limited by the thickness of the vertical cross bar. Some cages, however, have a horizontal cross bar adjacent to and spaced from the vertical cross bar. A horizontal cross bar also has an axially extending length, but has a circumferentially extending width and a radially thickness. Other cages do not have a horizontal cross bar per se, but do have a cross bar of L-shaped cross section with a slot cut through it, which effectively creates the equivalent structure. A horizontal cross bar presents much more available circumferentially extending surface area than the adjacent vertical cross bar.